1. Field of the Invention
The present invention relates to a solid-state imaging apparatus, a camera, and a method of manufacturing the solid-state imaging apparatus. In particular, the present invention relates to a solid-state imaging apparatus provided with a light-shielding unit such that an opening through which light is transmitted is formed in an area corresponding to the light-receiving surface of a photoelectric conversion unit in an image-sensing area of a substrate, to a camera, and to a method of manufacturing the solid-state imaging apparatus.
2. Description of the Related Art
Cameras, such as digital video cameras or digital still cameras, include a solid-state imaging apparatus. For example, such cameras have CCD (Charge Coupled Device) image sensors as solid-state imaging apparatuses.
In solid-state imaging apparatuses, an image-sensing area in which a plurality of pixels are arranged in a matrix in the horizontal direction and in the vertical direction is provided on the surface of a semiconductor substrate. In this image-sensing area, a plurality of photoelectric conversion units that receive light of an object image and generate signal charge by performing photoelectric conversion of the received light are formed so as to correspond to the plurality of pixels. For example, photodiodes are formed as these photoelectric conversion units.
Then, for example, in the case of a CCD image sensor, vertical transfer register units are provided between the columns of a plurality of photoelectric conversion units arranged in the vertical direction in the image-sensing area. The vertical transfer register unit is provided with a plurality of transfer electrodes that are provided so as to oppose a vertical transfer channel with a gate insulating film in a vertical transfer channel area provided therebetween, so that signal charge read from the photoelectric conversion unit by the charge reading unit is transferred in the vertical direction.
Then, the signal charge transferred for each horizontal line (pixels in one row) by the vertical transfer register unit is sequentially transferred in the horizontal direction by the horizontal transfer register unit, and the output unit outputs the signal charge. Furthermore, in order to prevent an occurrence of a problem, such as smearing, the image-sensing area is provided with a light-shielding film so as to prevent light from entering the vertical transfer register unit.
It has been proposed that, in this CCD image sensor, transfer electrodes are provided so as to function as charge reading electrodes. Here, transfer electrodes are formed so as to oppose a vertical transfer channel area and a charge readout channel area with a gate insulating film provided therebetween (see, for example, Japanese Unexamined Patent Application Publication No. 2005-140411 (Claim 1, FIGS. 2 to 5, etc.)).
Furthermore, it has been proposed that a light-shielding film is provided so as to have a function of a charge reading electrode in addition to the light-shielding function. Here, a light-shielding film is formed using a conductive material on a transfer electrode with an interlayer insulating film provided therebetween, and this light-shielding film is provided so as to include a portion opposing the electric charge readout channel area with the gate insulating film provided therebetween (see, for example, Japanese Unexamined Patent Application Publication No. 2005-109021 (Claim 1, FIGS. 2 to 4, etc.)).
In addition to this, it has been proposed that a light-shielding film is provided so as to function as a transfer electrode (see, for example, Japanese Unexamined Patent Application Publication No. 10-223876 (Claim 1, etc.)).